48 Mr. H. W. Bates on the Longicorn Coleoptera 



is, however, an error, the credit of pointing out which is due 

 to M. Thomson in his recent work on the Cerambycides. A 

 deep depression around the base of the tubercle seems to have 

 given rise to the mistake ; but in fact the depression, which is 

 found also in great numbers of Lamiaires, is not continuous, as 

 a slight examination will show. 



1. A. longimanus, Linn, and authors. 



The Amazonian examples of this insect are smaller than those 

 found in other parts of South America. It is not a very com- 

 mon insect, and is not found, as its great size would lead one 

 to suppose, on the larger trees of the forest ; I have found it 

 almost always on slender boughs, or on tree trunks of moderate 

 dimensions. I have sometimes cut the insect out of the rather 

 hard wood of such trees, near the centre of which it passes the 

 larva and pupa states. The stridulation of the species is very 

 loud, and can be heard at many yards' distance in the forest. 

 It appears not to be confined to one kind of tree ; I have found 

 it on the Inga, a genus of Leguminosse, and on the Jabuti-puhe, 

 a wild fruit-tree of the order Anonacese, as well as other trees. 

 On the Inga it is sometimes seen in company with Oreodera 

 glauca, — the Oreodera being coloured in close imitation of the 

 bark, and clinging very closely and flatly to it, thus eluding 

 observation, whilst A. longimanus in its bright colours forms 

 a very conspicuous object. It is very slow in motion, but has 

 the habit of bending its long legs rigidly in self-defence on 

 being disturbed. Thus, of two allied species, one has the means 

 of defence and maintenance of existence in one way, and one 

 in another. 



2. A. trochlearis, Linn. 



Cerambyx trochlearis, Linn. Syst. Nat. ii. 622. 

 Prionus trochlearis, Oliv. Col. iv. 7- 13- 49. 



This elegant species seems to be peculiar to Guiana and the 

 Amazon region. Its habits are similar to those of A. longi- 

 manus, in so far as it is found on the moderate-sized branches 

 of trees blown down in the forest. 



The allied A. accentifer I did not meet with ; it is found in 

 S.E. Brazil and in Venezuela, but not in the intermediate 

 country of Amazonia. 



Genus Oreodera. 



Serville, Ann. Soc. Ent. Fr. iv. 19. 



The body in this, as in the preceding genus, is elongated and 

 flattened ; the species, however, are of much smaller size. The 

 prothorax has on its disk three prominent tubercles, arranged in 



